Intradermal pen adapter

ABSTRACT

An intradermal injection adapter includes a body having a longitudinal axis and a central portion located distally relative to the body along the longitudinal axis. The central portion has a cannula channel therethrough extending generally parallel to the longitudinal axis. A cannula within the cannula channel has a sharpened tip for injection into a patient and a sharpened opposite proximal end for injection into a pen injector. A distal protrusion has a first skin contacting surface extending generally parallel to the longitudinal axis. The first skin contacting surface is spaced from the cannula such that a distal portion of the cannula extends generally parallel to the first skin contacting surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Non-Provisional of Provisional Application No.61/461,650, entitled “Intradermal Pen Adapter”, filed Jan. 21, 2011, thecontents of which are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION

Intradermal injections are used for delivering a variety of diagnosticand treatment compositions into a patient. Intradermal injections aretypically injections of a relatively small amount of medicament into thedermis or dermal layer or even into a lower portion of the epidermis(FIG. 2A) of a patient's skin. Substances may be injected intradermallyfor diagnostic testing, such as to determine a patient's immunity statusagainst tuberculosis and the status of allergic diseases. Vaccines,drugs and other compounds may also be delivered intradermally. In manyinstances, intradermal delivery is preferred because it generallyrequires a smaller volume dose of the diagnostic or treatment compoundthan other delivery techniques. There is considerable variation in thethickness of a patient's skin, both between individuals and within thesame individual at different sites of the body. Generally the outer skinlayer, or the epidermis, typically has a thickness between two hundredand five hundred microns (200-500 μm) and the dermis, the inner andthicker layer of the skin, generally has a thickness between one andone-half to three and one-half millimeters (1.5-3.5 mm).

Making intradermal injections is difficult and generally requires anexperienced nurse or medical professional. Incorrect placement of thetip of the cannula may lead to a failed injection. The placement of thecannula tip deeper than about three millimeters (3.0 mm) has thepotential of delivering the injection into the subcutaneous region,where the intradermal dosage may be insufficient. Incorrect placement ofthe cannula may also puncture the skin again after being inserted intodermis, with the delivered compound being lost on the surface of theskin. Injection is often followed by a jet effect, with the compoundexiting the injection site through the puncture track. The jet effect iseven more pronounced for injections through a cannula placedperpendicular to the injection site and in particular for shallowdelivery. The success of intradermal injections is often determined bythe skill and experience of the individual healthcare professionaladministering the injection. The preferred intradermal injectiontechnique (using a standard cannula), requires the healthcareprofessional to stretch the skin, orient the cannula bevel to faceupward, and insert a short bevel cannula at an angle of around ten tofifteen degrees (10-15°) relative to a surface of the skin, while alsoassuring that two to three millimeters (2-3 mm) of the cannula arelocated in the skin. The cannula tip ideally ends up positioned in thedermis or close to the dermis/epidermis boundary. The compound is slowlyinjected into the skin of the patient, forming a blister or wheal. Theinsertion of the cannula at an incorrect angle and/or depth results in afailed intradermal injection, which is typically repeated, causingadditional pain and discomfort as well as ineffective treatment to thepatient. Intradermal (ID) injection has been considered for immunizationin the past, but has generally been rejected in favor of more reliableintramuscular or subcutaneous routes of administration because of thedifficulty in making a successful ID injections, particularly when theinjections are administered by relatively unskilled healthcareprofessionals.

Administration into the region of the intradermal space has beenroutinely used in the Mantoux tuberculin test, in which a purifiedprotein derivative is injected at a shallow angle to the skin surfaceusing a twenty-seven (27) or thirty (30) gauge cannula and a standardsyringe. The technique is known to be quite difficult to perform andgenerally requires specialized training. A degree of imprecision in theplacement of the injection results in a significant number of falsenegative test results. As a result, the Mantoux approach has not led tothe use of intradermal injection for systemic administration ofsubstances, despite the advantage of requiring smaller doses ofsubstances, because the absorption of the medicament into the dermalskin layer is typically superior to injection of the same substanceusing alternative techniques.

It would be desirable to design and manufacture an intradermal injectionadapter that provides a relatively simple, reliable intradermalinjection, is relatively easy to use, is relatively cost effective tothe user and limits waste of medicament. The cannula of the intradermalinjection adapter is preferably statically mounted to or fixed relativeto a body of the adapter and/or a barrel of a syringe or pen in anassembled configuration.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, in a preferred aspect, the present application isdirected to an intradermal injection adapter having a body defining alongitudinal axis and a central portion located distally relative to thebody along the longitudinal axis. The central portion has a cannulachannel therethrough extending generally parallel to the longitudinalaxis. A cannula fixed within the cannula channel has a sharpened tip forinjection into a patient and a sharpened opposite proximal end forinjection into a pen injector. A distal protrusion has a first skincontacting surface extending generally parallel to the longitudinalaxis. The first skin contacting surface is spaced from the cannula suchthat a distal portion of the cannula extends generally parallel to thefirst skin contacting surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, will be better understood when read in conjunction withthe appended drawings. For the purpose of illustrating the invention,there are shown in the drawings embodiments which are presentlypreferred. It should be understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown.

FIG. 1 is a top perspective view of a syringe and an adapter inaccordance with a first preferred embodiment of the present invention;

FIG. 2 is a side elevational view of the syringe mounted to the adapterof FIG. 1 in an assembled configuration with the cannula inserted into apatient's skin in the process of making an intradermal injection;

FIG. 2A is a cross-sectional view of the patient's skin taken fromwithin box 2A of FIG. 2;

FIG. 3 is a front perspective view of the adapter of FIG. 1;

FIG. 4 is a side elevational view of the adapter of FIG. 1;

FIG. 5 is a rear perspective view of the adapter of FIG. 1;

FIG. 6 is a top perspective view of an adapter in accordance with asecond preferred embodiment of the present invention;

FIG. 7 is a right-side elevational view of the adapter of FIG. 6;

FIG. 8 is a side elevational view of a pen injector and an adapter inaccordance with a third preferred embodiment of the present invention;

FIG. 9 is a magnified side elevational view of a portion of the combinedpen injector and adapter of FIG. 8;

FIG. 10 is a magnified perspective view of the adapter and a portion ofthe pen injector of FIG. 8, wherein the adapter is shown separated andspaced-apart from the pen injector;

FIG. 11 is a side elevation view of the combined pen injector andadapter of FIG. 8; and

FIG. 12 is a top perspective view of the adapter of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right,” “left,” “lower,” and“upper” designate directions in the drawings to which reference is made.The words “inwardly” or “proximally” and “outwardly” or “distally” referto directions toward and away from, respectively, the geometric centeror orientation of the adapter, adapter and syringe assembly, adapter andpen assembly, or other related parts thereof. The words, “connect,”“connectable” and “connected” mean joined or linked together, either bydirect engagement or through intermediate components. The terminologyincludes the above-listed words, derivatives thereof and words ofsimilar import.

Referring to FIGS. 1-5, a first preferred embodiment of the presentinvention is directed to an intradermal injection adapter 10 formounting to a syringe 12 having a cannula 14 for making an intradermalinjection in a patient's skin S. In the first preferred embodiment, theadapter includes a side opening 22 that extends along an entire lengthof the adapter 10, generally parallel to the longitudinal axis 18. Theside opening 22 permits insertion of the syringe 12 into the adapter 10for injecting medicament into a patient in an assembled configuration,wherein a tip 14 a of a cannula 14 is spaced distally relative to acannula channel edge 26 a of the adapter 10 and is generally fixed inthis position in the assembled configuration. The side opening 22specifically permits a medical professional to engage the syringe 12with the adapter 10 prior to injection of the medicament into thepatient. Typically, the adapter 10 is packaged in a sterile package andremoved from the package for assembly with the syringe 12 prior toinjecting the medicament into the patient. Accordingly, a plurality ofpackaged adapters 10 and a plurality of syringes 12 can be stored at aninjection site and assembled when necessary for injecting medicamentinto patients.

The adapter 10 is not limited to inclusion of the side opening 22 (seeFIGS. 6-7), but the side opening 22 permits relatively easy assembly orengagement of the syringe 12 with the adapter 10. For example, theadapter 22 may be sold as an individual, sterile unit to a medicalorganization or other user and mounted to a pre-filled syringe 12 beforeinjection of the medicament into the skin S. However, the adapter 10 mayalso be configured to eliminate the side opening 22 such that thesyringe 12 is introduced into the syringe channel 20 through a proximalend portion 16 a of a body 16 of the adapter 10 (see FIGS. 6-7). Inaddition, the adapter 10 may be configured such that the adapter 10 ispermanently affixed to or molded to the syringe 12 wherein the body 16is permanently attached, adhesively bonded, formed or is otherwisepermanently affixed or attached to the syringe 12. The adapter 10 ispreferably used by healthcare professionals, but may also be used bynon-healthcare professionals, potentially for self-injection andtypically when the adapter 10 is pre-assembled to the syringe 12.

The intradermal injection adapter 10 also includes a central portion 24having a cannula channel therethrough extending generally parallel tothe longitudinal axis 18. The cannula channel defines the cannulachannel edge 26 a that tapers slightly distally in the first preferredembodiment, but may be oriented generally perpendicular or otherwise tothe longitudinal axis 18. For example, the cannula channel edge 26 a maybe oriented in various configurations or at various orientations toaccommodate introduction of the cannula 14 into the cannula channel 26,to align the cannula 14 with the adapter 10 or for various other designconsiderations. In the assembled configuration, at least a portion ofthe cannula 14 is received within the cannula channel 26 and a distalportion of the cannula 14 extends beyond the cannula channel 26. Thecannula channel edge 26 a is not limited to being positioned generallyperpendicular to the longitudinal axis 18 and may be pitched orotherwise oriented relative to the longitudinal axis 18 and is slightlypitched relative to the longitudinal axis 18 in the first preferredembodiment (see FIG. 4).

In the first preferred embodiment, a demarcation plane 27 is definedwhere the cannula 14 extends over the channel edge 26 a, is generallyperpendicular to the longitudinal axis 18 and intersects thelongitudinal axis 18. The tip 14 a of the cannula 14 is positioneddistally relative to the demarcation plane 27 when the syringe 12 andthe adapter 10 are in the assembled configuration and the cannula 14 andtip 14 a generally maintain their position relative to the demarcationplane 27 in the assembled configuration and through the injectionprocess.

In the first prepared embodiment, a second skin contacting surface 28extends proximally from the cannula channel edge 26 a at a taper angleΔ. The taper angle Δ may be set or adapted to accommodate dimensions ofthe adapter 10 and/or the associated syringe 12. At least a portion ofthe second skin contacting surface 28 preferably tapers proximally fromthe channel edge 26 a at a relatively shallow angle such that the secondskin contacting surface 28 may smoothly slide along the patient's skinS. The second skin contacting surface 28 is not limited to beinggenerally planar or conical, may be oriented at different angles, mayhave a portion that is generally perpendicular relative to thelongitudinal axis 18 (see FIG. 7), may be arcuate or slightly curved oreven have a portion that is generally linear and additional portionsthat are arcuate and/or curved.

A distal protrusion 30 extends generally parallel to the longitudinalaxis 18 from the central portion 24. In the first preferred embodiment,the distal protrusion 30 includes a sloped distal nose 32 that curvesaway from the longitudinal axis 18. The sloped or curved distal nose 32assists the user or medical professional in arranging the adapter 10relative to the patient's skin S and generally limits scrapping or roughengagement of the distal nose 32 with the patient's skin S to limit thepatient's pain and discomfort. The sloped or curved distal nose 32 alsopromotes a relatively smooth sliding of the adapter 10 along thepatient's skin S while inserting the cannula 14 into the patient's skinS and guiding the adapter 10 along a path generally parallel or slightlypitched relative to the patient's skin S such that the cannula 14 isinserted into the patient's skin S with the tip 14 a positioned in thedermis or dermal layer. The distal protrusion 30 is not limited toinclusion of the distal nose 32 that generally slopes away from thelongitudinal axis 18 and may include a blunt-edge at a distal end, maybe tapered or may be otherwise configured to assist the user or medicalprofessional in positioning the adapter 10 relative to the patient'sskin S.

In the first preferred embodiment, the distal protrusion 30 is generallytransparent distally relative to the demarcation plane 27 such that thecannula 14 can be viewed through the distal protrusion 30 duringinsertion of the cannula 14 into the skin S and generally during theentire intradermal injection process. Having a generally transparentdistal protrusion 30 permits the medical professional, nurse or even thepatient to view the cannula 14 through the distal protrusion 30 toensure that the cannula 14 and, particularly, the tip 14 a is insertedinto the patient's skin S during injection. For example, a medialprofessional may position the cannula 14 relative to the user's skin andinadvertently fail to penetrate the skin S in sloped or rough areas.Such a mis-insertion may cause the user or medical professional toactivate the syringe 12 to eject the medicament without the tip 14 apositioned in the skin S, thereby losing or wasting the medicament.Ejecting the medicament with a mis-placed cannula 14 wherein the cannula14 is not positioned in the dermal layer of the patient's skin S wastesthe medicament, which can be relatively expensive and often requires asecond injection, thereby typically causing additional pain anddiscomfort for the patient. Such a situation may also result in thepatient not being vaccinated, potentially without the knowledge of themedical professional or other user. Accordingly, it is preferred thatthe distal protrusion 30 is relatively transparent such that the medicalprofessional, nurse and/or patient can confirm that the cannula 14 ispositioned beneath the surface of the patient's skin S prior toinjection. However, the distal protrusion 30 is not limited to beinggenerally transparent and may be opaque.

The distal protrusion 30 includes a first skin contacting surface 34that extends generally parallel to the longitudinal axis 18. In theinjecting position, the first skin contacting surface 34 contacts thesurface of the patient's skin S to position the tip 14 a of the cannula14 at a predetermined depth into the skin S such that the tip 14 a ispositioned in the dermal layer of the skin S and the medicament isinjected into the dermal layer for absorption. The first skin contactingsurface 34 is preferably not discontinuous or does not include anopening or hole at or near the tip 14 a to limit the potential that theskin S pushes into the opening or hole, thereby causing the tip 14 a tobe positioned too deep into the patient's skin S or even in asubcutaneous space. Accordingly, the generally continuous first skincontacting surface 34 generally controls a distance between the tip 14 aof the cannula 14 and the first skin contacting surface 34 to increasethe likelihood that the tip 14 a is positioned in the dermal layer in aninjection position (FIG. 2).

In the first preferred embodiment, a first alignment ramp 36 ispositioned within the cannula channel 26 and is configured to orient thecannula 14 generally parallel to the first skin contacting surface 34 inan assembled configuration (FIG. 2). Orienting the cannula 14 generallyparallel to the first skin contacting surface 34 is preferred to controlthe spacing of the cannula 14 relative to the first skin contactingsurface 34 such that the tip 14 a is positioned in the dermal layer ofthe patient's skin S in the injection position (FIG. 2).

The adapter 10 of the first preferred embodiment also includes a secondalignment ramp 38 positioned within the cannula channel 26 that isconfigured to orient the cannula 14, in cooperation with the firstalignment ramp 36, generally parallel with the first skin contactingsurface 34 in the assembled configuration. The second alignment ramp 38is preferably positioned distally in the cannula channel 26 relative tothe first alignment ramp 36 and the cannula 14 is preferably in facingengagement with the first and second alignment ramps 36, 38 in theassembled configuration. The adapter 10 is not limited to inclusion ofeither the first alignment ramp 36 or the second alignment ramp 38 toalign at least the distal section of the cannula 14 generally parallelto the first skin contacting surface 34 and may include numerousalternative alignment mechanisms or no specific alignment mechanism inthe central portion 24 or within the cannula channel 26. For example,the cannula channel 26 may include a V-shaped groove that aligns thecannula 14 generally parallel to the first skin contacting surface 34, aclamping mechanism that aligns the cannula 14 with the first skincontacting surface 34 or numerous alternative alignment mechanisms topreferably arrange the cannula 14 generally parallel to the first skincontacting surface 34. In addition, the cannula 14 is not necessarilyoriented generally parallel to the first skin contacting surface 34 andmay be alternatively arranged such that the tip 14 a of the cannula 14is configured for positioning in the dermal layer of the skin S withoutbeing aligned generally parallel to the first skin contacting surface34.

The cannula channel 26 is defined by the first skin contacting surface34, the lateral cannula wall 40 and the alignment wail 42 in the firstpreferred embodiment and is generally contained in the central portion24. The cannula 14 is preferably positioned adjacent the lateral cannulawall 40 in the assembled configuration. Accordingly, the first andsecond alignment ramps 36, 38 and the lateral cannula wall 40 align thecannula 14 generally parallel to the first skin contacting surface 34 inthe assembled configuration and generally center the cannula 14 alongthe longitudinal axis 18 in the assembled configuration. However, thecannula 14 is not limited to being aligned and centered utilizing thefirst and second alignment ramps 36, 38 and the lateral wall 40 as wasdescribed above and may be otherwise aligned and oriented by the adapter10 such that the tip 14 a is positioned in the dermal layer of thepatient's skin in the injecting configuration. In addition, the cannula14 is not limited to being generally coaxial with the longitudinal axis18 in the assembled configuration and may be mis-aligned or slightlypitched relative to the longitudinal axis 18 as long as the tip 14 isgenerally positioned in the dermal layer in the injection position.

Referring to FIG. 4, the first skin contacting surface 34 is spaced arelatively consistent distance from the distal portion of the cannula14. The first skin contacting surface 34 is also generally continuousbetween an area adjacent a tip 14 a of the cannula 14 and an areaadjacent the channel edge 26 a in the assembled configuration. In thefirst preferred embodiment, the syringe 12 may be generally coaxial withthe longitudinal axis 18 and the distal portion of the cannula 14 ispitched slightly upwardly away from the longitudinal axis 18 to comeinto generally parallel alignment with the first skin contacting surface34 in the assembled configuration. The distal portion of the cannula 14is preferably spaced at a cannula gap distance X from the first skincontacting surface 34. The cannula gap distance X is preferably at leasttwo tenths of a millimeter (0.2 mm) and may be within a range of twotenths of a millimeter to two millimeters (0.2-2 mm). However, thecannula gap distance X is not limited to being in this range and may becomprised of nearly any distance that permits the tip 14 a of thecannula 14 to be positioned in the dermal layer of the patient's skin Sin the injection position. In the first preferred embodiment, thecannula gap distance X is approximately fifty-five hundredths of amillimeter (0.55 mm). In addition, a more preferred range for thecannula gap distance X is approximately four tenths of a millimeter toeight tenths of a millimeter (0.4-0.8 mm). The cannula 14 of the firstpreferred embodiment may be a cannula gage 27 and the cannula gapdistance X between the first skin contacting surface 34 and an outerdiameter of the cannula 14 may be fifty-five hundredths of a millimeter(0.55 mm) or greater, generally resulting in the tip 14 a of the cannula14 being positioned within the dermal layer in the injection position.The cannula gap distance X may be impacted by the orientation of thecannula 14 (lancet up or lancet down), gage of the cannula 14, expectedlocation of injection in the patient and numerous other factors that maybe considered by the designer.

In the first preferred embodiment, the tip 14 a of the cannula 14 ispositioned approximately one and one-half to ten millimeters (1.5-10 mm)along the longitudinal axis 18 from the demarcation plane 27 definedwhere the cannula 14 extends over the channel edge 26 a. The demarcationplane 27 intersects and is generally perpendicular to the longitudinalaxis 18. In the first preferred embodiment, the tip 14 a of the cannula14 is positioned distally beyond the demarcation plane 27, defined wherethe cannula 14 extends over the channel edge 26 a, at an exposed lengthL₁. The exposed length L₁ is not limited to the above-described one andone-half to ten millimeters (1.5-10 mm) and may have nearly any lengththat permits insertion of the tip 14 a into the dermal layer of thepatient's skin S in the injection configuration. In a more preferredrange, the exposed length L₁ is approximately two and one-half to sevenmillimeters (2.5-7 mm) and in a further preferred range, the exposedlength L₁ is approximately two and one-half to four millimeters (2.5-4mm). In the assembled configuration, the exposed length L₁ is preferablypredetermined during the design of the adapter 10 and the cannula 14generally does not move or slide relative to the adapter in theassembled configuration. Accordingly, once the syringe 12 is engagedwith the adapter 10 of the first preferred embodiment, the exposedlength L₁ generally does not change and the cannula 14 and associatedsyringe 12 do not slide relative to the body 16, the central portion 24and the distal protrusion 30.

The distal protrusion 30 of the first preferred embodiment is generallyclear or transparent, at least distally toward the distal nose 32relative to the demarcation plane 27, and is generally cloudy or opaqueproximally of the demarcation plane 27. The central portion 24 and theremainder of the adapter 10 are also preferably cloudy or opaque.Providing a generally transparent distal protrusion 30, at leastdistally of the demarcation plane 27, and a generally opaque distalprotrusion 30 and adapter 10 proximally of the demarcation plane 27provides a visual cue to a medical professional or user that the cannula14 is penetrating the skin S during injection and that the skin S is infacing engagement with the first skin contacting surface 34 in theinjection position. The distal portion of the cannula 14 may appear todisappear or be completely positioned beneath the skin S in theinjection position due to the generally transparent distal protrusion 30distally relative to the demarcation plane 27 and cloudy or opaqueremainder of the adapter 10, as the proximal portion of the cannula 14that is positioned proximally to the demarcation plane 27 may beobscured by the opaque or cloudy portions of the adapter 10. Thisdisappearance of the cannula 14 also provides a visual cue to themedical professional or user that the cannula 14 penetrates the skin S asufficient distance and additional insertion pressure or force is notrequired to insert the cannula 14. This visual cue can be particularlyuseful for “heavy-handed” medical professionals or users who may applyexcessive pressure in the injection position and potentially cause skinS to bunch between the first skin contacting surface 34 and the cannula14, which could cause damage to the cannula 14 or result in the tip 14 abeing positioned outside of the intradermal layer.

Designing the distal protrusion 30 with a generally transparent portiondistally and a generally opaque portion proximally of the demarcationplane 27 permits the medical professional or user to visually confirmthat the distal portion of the cannula 14 that extends beyond thecannula channel edge 26 a has entered the patient's skin S and the skinS is in relatively consistent contact with the first skin contactingsurface 34, which provides a visual indication to the medicalprofessional or user that the tip 14 a of the cannula 14 is positionedin the dermis or dermal layer of the patient's skin S such that themedicament will be injected into the dermis or dermal layer of thepatient's skin S for absorption into the patient's body.

In the first preferred embodiment, a tip 14 a of the cannula 14 ispreferably spaced at an overhang length L₂ from a distal edge of thedistal nose 32 (see FIG. 4). The overhang length L2 is preferably atleast one millimeter (1 mm), particularly if the adapter 10 does notinclude the upturned distal nose 32. In the first preferred embodiment,the overhang length L₂ is approximately two to six millimeters (2-6 mm).The overhang length L₂ provides some safety to users and patients fromreceiving an inadvertent puncture from exposure to the tip 14 a, forexample, if a medical professional attempts to introduce the cannulainto the skin S generally perpendicular to the skin S or inadvertentlyapproaches the skin S generally perpendicularly to the skin S, and alsoprovides a section of relatively constant cannula gap distance X betweenthe tip 14 a and the demarcation plane 27 in the assembled configurationto correctly position the tip 14 a in the skin S during insertion. Thecannula gap distance X is preferably consistent between the demarcationplane 27 and the tip 14 as a result of at least the distal portion ofthe cannula 14 extending generally parallel to the first skin contactingsurface 34. The first skin contacting surface 34 also preferably extendsbeyond the tip 14 a along a generally linear or parallel path, at leastfor a limited distance before the distal nose 32 begins to curveupwardly and this extended distance may be approximately one to twomillimeters (1-2 mm). The overhang length L₂ is not limited to theabove-described dimensions and may have nearly any dimension that limitsexposure to the tip 14 a and facilitates insertion of the cannula 14into the skin S at a desired depth from the surface of the skin S. Theoverhand length L₂ also generally prevents perpendicular insertion ofthe cannula tip 14 a into the patient's skin S. Attempts atperpendicular insertion of the cannula tip 14 a into the patient's skinS typically produces inaccurate positioning of the tip 14 a in thedermal layer and injection of the medicament into an undesirable sectionof the skin S.

Referring to FIGS. 1 and 2 in the first preferred embodiment, thesyringe 12 includes a barrel 44, a plunger 46 with a piston 46 aslidable and sealingly engaged within a hollow cavity 44 a of the barrel44 and the cannula 14. The barrel 44 a has a generally cylindricalconfiguration and the hollow internal cavity 44 a receives themedicament therein. The medicament is typically stored between thepiston 46 a and the cannula 14 in the hollow internal cavity 44 a. Thesyringe 12 is not limited to inclusion of the barrel 44, plunger 46 andcannula 14 and may be comprised of nearly any device that is able toretain medicament therein, be joined with the adapter 10 and expel themedicament therefrom or otherwise inject the medicament into the dermallayer of the patient's skin S in operation. For example, the syringe 12may be comprised of a pre-filled syringe 12 without a cannula 14 whereinthe cannula 14 is associated with the adapter 10 (see, e.g., FIGS. 11and 12).

In the first preferred embodiment, the adapter 10 includes at least thebody 16, the distal nose 32, the central portion 24 and the syringechannel 20 that extends generally parallel to the longitudinal axis 18through the body 16. The body 16 includes the syringe channel 20 and ispreferably positioned proximally on the adapter 10 relative to thecentral portion 24, which includes the cannula channel 26. The syringechannel 20 receives at least a portion of the syringe 12 and,particularly, at least a portion of the barrel 44 in the assembledconfiguration. The adapter 10 also includes the side opening 22 thatpreferably extends along an entire length of the adapter 10 between theproximal portion 16 a and the distal nose 32 or at least to the end ofthe central portion 24 near the cannula channel edge 26 a. The sideopening 22 permits selective insertion of the syringe 12 and cannula 14relative to or into the adapter 10. The side opening 22 is preferablyslightly narrowed relative to a maximum diameter of the barrel 44 suchthat the barrel 44 is force-fit or snap-fit into the syringe channel 20during assembly. The snap-fit or force-fit of the barrel 44 into thesyringe channel 20 assist in retaining the syringe 12 in the adapter 10following assembly. However, the barrel 44 is not limited to beingsnap-fit or force-fit into the syringe channel 20 and may bealternatively engaged or secured to the adapter 10 by staking, clamping,adhesive bonding, fastening or otherwise fastening or securing thesyringe 12 to the adapter 10.

In the first preferred embodiment, the configuration of the syringechannel 20 inside opening 22 defines a narrowed C-shaped clampingsection into which the syringe 12 is force fit in the assembledconfiguration.

Referring to FIG. 5, the distal protrusion 30 has a protrusion width Wof approximately three to ten millimeters (3-10 mm) to engage the skin Sin the injection position (FIG. 2). The protrusion width W is notlimited to the three to ten millimeter (3-10 mm) range and may havenearly any width that is maneuverable by the medical professional oruser and promotes proper placement of the tip 14 a in the dermal layeror dermis in the injection position. In the first preferred embodiment,the protrusion width W is approximately the same or slightly smallerthan the diameter of the barrel 44, but is not so limited. It may bepreferable for the protrusion width W to generally match or be slightlysmaller than the diameter of the barrel 44 for storage, packaging,maneuverability and overall handling of the syringe 12 and adapter 10.The protrusion width W is preferably configured to result inminimization of forces required during insertion while generallystabilizing the position of the adapter 10 relative to the skin S duringinsertion and in the injection position. The protrusion width W of thedistal protrusion 30 could be narrow relative to the barrel 44 tointegrate other system components or may be larger than the barrel 44 ofthe syringe 12 to generally maximize stability.

Referring to FIGS. 1-3, in the first preferred embodiment, the cannula14 has a cannula hub 14 b that is preferably, integrally engaged with anarrowed distal portion 44 b of the syringe 12. The cannula 14 ispreferably constructed of a metal material that is bonded into thecannula hub 14 b, which is typically constructed of a polymeric orplastic material. The adapter 10 also preferably includes a positioningwall 48 that is engaged with the narrowed distal portion 44 b of thebarrel 44 in the assembled configuration. Engagement of the narroweddistal portion 44 b and the positioning wall 48 generally controls thepositioning of the tip 14 a of the cannula 14 relatively along thelongitudinal axis 18 to obtain the desired exposed length L₁ andoverhang length L₂. Accordingly, the adapter 10 is preferably configuredfor syringes 12 and cannulas 14 having known dimensions, at least withrespect to the position of the narrowed distal portion 44 b relative tothe tip 14 a of the cannula 14 such that the positioning of the tip 14 arelative to the adapter 10 is controllable. The syringe channel 20 isalso designed and configured to receive and retain the barrel 44 of thesyringe 12 in the assembled configuration.

In the first preferred embodiment, the adapter 10 includes a collar 50at the proximal end portion 16 a that can be utilized by a user tohandle the adapter 10. The collar 50 may be used to engage the adapter10 with the user's fingers to maintain the syringe 12 in a properposition relative to the adapter 10.

The adapter 10 also preferably includes a finger grasping portion 52that can be utilized by the medical professional or nurse to grasp andhold the adapter 10 and syringe 12 during use. The finger graspingportion 52 permits the medical professional or nurse to grasp theadapter 10 and syringe 12 proximate the distal nose 32 to providecontrol close to the tip 14 a. During injection, the medicalprofessional typically manipulates the assembled adapter 10 and syringe12 by grasping the barrel 44 and/or the adapter 10.

Referring to FIGS. 6 and 7, in a second preferred embodiment, an adapter10′ has a similar configuration to the adapter 10 of the first preferredembodiment, but the cannula 14′ is fixed to the adapter 10′, the body16′ does not include a side opening for receipt of the syringe 12′, aswell as additional structural and functional differences between thefirst and second embodiment. The adapter 10′ of the second preferredembodiment utilizes the same reference numerals to identify similarfeatures relative to the adapter 10 of the first preferred embodimentand a prime symbol (′) to specifically identify the adapter 10′ of thesecond preferred embodiment and its components. Accordingly, asignificant number of the features of the second preferred embodiment ofthe adapter 10′ are the same or similar to the adapter 10 of the firstpreferred embodiment and the features that are different in the adapter10′ of the second preferred embodiment are emphasized in the belowdescription.

In the second preferred embodiment, the cannula 14′ is fixed to theadapter 10′ such that the tip 14 a′ is positioned relative to the distalprotrusion 30′ with the exposed length L₁′ and the overhang length L₂′predetermined and typically falling within the above-describedpredetermined ranges of the first preferred embodiment. In addition, thecannula gap distance X′ is also predetermined and preferably fallswithin the above-described preferred ranges of the first preferredembodiment. Fixing the cannula 14′ to the adapter 10′ generallyeliminates potential mis-alignment of the cannula 14′ relative to theadapter 10 and, therefore, mis-positioning of the tip 14 a′ relative tothe distal protrusion 30′.

In the second preferred embodiment, the adapter 10′ is typicallyassociated with a pre-filled syringe (not shown) without the cannula 14′mounted thereto and is typically attached to the proximal end portion 16a′ of the body 16′ using a conventional Luer. The syringe 12′ may bepre-filled by the manufacturer, filled by the medical professional oruser prior to injection or otherwise filled prior to engaging theadapter 10′ with the pre-filled syringe 12′ using a cannula, vialadapter, spike or other mechanism. The syringe 12′ is not limited tobeing mounted to the body 16′ by a Luer in the second preferredembodiment and may be otherwise mounted, secured or fastened to the body16′.

Referring to FIGS. 8-12, in a third preferred embodiment, an adapter 10″has a similar configuration to the adapters 10, 10′ of the first andsecond preferred embodiments, but the adapter 10″ of the third preferredembodiment is designed for use with a pen injector 12″ or any othermulti-dose, pre-filed automatic injection device, such as those used forthe self-injection of insulin. Additional differences between the thirdpreferred embodiment of the adapter 10″ and the other embodiments aredescribed below or can generally be identified in the figures. Theadapter 10″ of the third preferred embodiment utilizes the samereference numerals to identify similar features relative to the adapters10, 10′ of the first and second preferred embodiments and a double-primesymbol (″) to specifically identify the adapter 10″ and its componentsof the third preferred embodiment. Accordingly, a significant number ofthe features of the third preferred embodiment of the adapter 10″ arethe same or similar to the adapters 10, 10′ of the first and secondpreferred embodiments and the features that are different in the thirdpreferred embodiment of the adapter 10″ are emphasized in the belowdescription.

In the third preferred embodiment, the pen injector 12″ includes amedicament storage volume 44″ (for example, a vial, cartridge, or peninjector barrel) and an injection button 45″ operatively coupled to aplunger 46″ with a piston 46 a″ slidable within a hollow cavity 44 a″ ofthe storage volume 44″. The pen injector 12″ may include a rotatabledial or a depressible button 66″ to allow a user to selectively adjustthe dosage of medicament. The pen injector 12″ typically includes adrive mechanism (known in the art and not illustrated) to effectuatemovement of the piston 46 a″ to expel the medicament. The storage volume44″ generally has a cylindrical configuration and the hollow internalcavity 44 a″ receives the medicament therein. The medicament istypically stored between the piston 46 a″ and a penetrable seal 64″ ofthe storage volume 44″ in the hollow internal cavity 44 a″. Depending onthe configuration of the storage volume 44″, the seal 64″ may connect toan open end of a vial or a cartridge, or to an opening within the distalend of the pen injector 12″ barrel. The person of ordinary skill in theart will recognize that adapter 10″ could be configured for use withnearly any known syringe device that is able to retain medicamenttherein, be joined with the adapter 10″ and expel the medicamenttherefrom or otherwise inject the medicament into the dermal layer ofthe patient's skin S in operation.

In the third preferred embodiment and similar to the second preferredembodiment, a cannula 14″ is fixed to the adapter 10″ such that a tip 14a″ is positioned relative to a distal protrusion 30″ with an exposedlength L₁″ and an overhang length L₂″ predetermined and typicallyfalling within the above-described predetermined ranges of the firstpreferred embodiment. In addition, a cannula gap distance X″ is alsopredetermined and preferably falls within the above-described preferredranges of the first preferred embodiment. The adapter 10″ is typicallyattached to a distal end 62″ of the pen injector 12″ using a threadedconnection, such that a body 16″ of the adapter 10″ preferably includesone or more threads on an interior surface thereof for attachment to thedistal end 62″ of the pen injector 12″. Alternatively, the adapter 10″may be configured to connect with other known pen injector 12″connections, such as that disclosed in U.S. Pat. No. 7,762,994, which isincorporated by reference herein in its entirety.

The entire or almost the entire adapter 10″ may be transparent orgenerally transparent, as shown in FIGS. 11 and 12, or only a portion ofthe adapter 10″ may be transparent, as described above with respect tothe first and second preferred embodiments. Alternatively, the entire oralmost the entire adapter 10″ may be opaque or generally opaque, asshown in FIGS. 8-10.

In the third preferred embodiment, the cannula 14″ is a dual tippedneedle or a double end needle. In other words, in addition to the distaltip 14 a″ of the cannula 14″ being sharp or pointed for injection intothe skin S of a patient, an opposite proximal end or tip 14 b″ of thecannula 14″ is sharp or pointed for injection into at least a portion ofthe hollow internal cavity 44 a″ of the storage volume 44″ of the peninjector 12″. The distal tip 14 a″ and opposite proximal end 14 b″ ofthe cannula 14″ are preferably identical or nearly identical in size andshape. Thus, the proximal end 14 b″ of the cannula 14″ is easily capableof penetrating the seal 64″ of the pen injector 12″, so that medicamentor other fluid can flow from the pen injector 12″, through the cannula14″ and into the patient's skin S.

Referring to FIGS. 1-5, in operation of the first embodiment of theadapter 10, the syringe 12 is either provided pre-filled or themedicament is aspirated into the syringe 12 from a vial (not shown). Thesyringe 12 may be separate from the adapter 10 to aspirate themedicament into the syringe 12 and a different cannula 14 may beutilized to aspirate the medicament into the syringe 12 than is used toinject the medicament into the patient. For example, a relatively largegage cannula 14 may be used to aspirate the medicament into the barrel44 and the relatively large gage cannula 14 may be replaced with asmaller gage cannula 14 for injection. Alternatively, the centralportion 24 and distal protrusion 30 may be hingedly mounted to thebarrel 44 and/or hub 14 b and the cannula 14 such that the centralportion 24 and distal protrusion 30 may be pivoted away from the cannula14 during aspiration of medicament from the vial into the syringe 12 andthen pivoted back into the assembled configuration for the injectionprocedure.

After medicament is in the syringe 12, the syringe 12 is mounted to theadapter 10. Preferably, the syringe 12 is press-fit through the sideopening 22 into the syringe channel 20 to engage the syringe 12 with theadapter 10. In the assembled configuration, the narrow distal portion 44b is preferably positioned in facing engagement with the positioningwall 48 to properly locate the tip 14 a relative to the adapter 10. Oncethe narrow distal portion 44 b is positioned in facing engagement withthe positioning wall 48, the cannula 14 generally does not move relativeto the adapter 10.

In the preferred assembled configuration, at least a portion of thecannula 14 is positioned within the cannula channel 26. During insertionfrom the side, the cannula 14 is guided into the cannula channel 26 bymoving along the upslope surfaces 36 a, 38 a of the first and secondalignment ramps 36, 38, over the apex surfaces 36 b, 38 b and along thedownslope surfaces 36 c, 38 c. In the assembled configuration, thecannula 14 is preferably positioned in facing engagement with thedownslope surfaces 36 c, 38 c and the lateral cannula wall 40.Positioning of the needle 14 in this configuration urges the cannula 14into generally parallel alignment with the first skin contacting surface34 such that the cannula 14 is spaced from the first skin contactingsurface 34 by the cannula gap distance X. The cannula gap distance X ispreferably predetermined such that the tip 14 a is positioned in thedermal layer of the patient's skin S in the injection position.

To inject the medicament into the patient's skin S, the user may graspthe finger grasping portion 52 and/or the barrel 44 and urge the adapter10 into engagement with the patient's skin S. The adapter 10 is orientedrelative to the patient's skin S such that the longitudinal axis 18 isslightly less than parallel or nearly parallel relative to the user'sskin S. Referring specifically to FIG. 2A, the adapter 10 may be urgedslightly downwardly toward the skin S and is subsequently urged towardor slides along the user's skin S such that at least the first skincontacting surface 34 is in engagement with a surface of the epidermisof the skin S. As the adapter 10 slides along the skin S, the distalnose 32 promotes relatively smooth sliding of the adapter 10 along theskin S. The cannula 14 generally does not move relative to the adapter10 during the injection process and the cannula 14 preferably enters theskin S for approximately the entire exposed length L₁. The medicalprofessional or user is able to visually inspect the cannula 14 enteringthe skin S and the surface of the epidermis contacting the first skincontacting surface 34 through the transparent distal portion of thedistal protrusion 30, which is demarcated by the preferred transparentto opaque transition of the distal protrusion 30 at the demarcationplane 27. In a fully engaged injection position, the user or medicalprofessional may visually observe that the entire portion of the cannula14 positioned distally of the demarcation plane 27 is positioned withinthe skin S. Accordingly, the medical professional may note that thecannula 14 is not visible through the relatively transparent portion ofthe distal protrusion 30 because the cannula 14 is located within theskin S. During insertion and injection, the medical professional ornurse is also able to view the tip 14 a entering the skin S through thegenerally transparent distal protrusion 30. In addition, the nurse ormedical professional is generally able to see the skin S contacting thefirst skin contacting surface 34 through the distal protrusion 30.Further, the first and second skin contacting surfaces 34, 28 promotepositioning of the cannula 14 relative to the skin S to further promotepositioning of the tip 14 a of the cannula 14 into the dermal layer. Inthe injection position, the tip 14 a of the cannula 14 is positioned inthe dermis of the skin S.

Once the tip 14 a of the cannula 14 is properly positioned in the skinS, the plunger 46 is depressed, thereby urging the piston 46 a to pushthe medicament out of the barrel 44, through the cannula 14, out of thetip 14 a and into the dermal layer. The medicament is absorbed into thedermal layer to provide clinical benefits to the patient.

The cannula gap distance X is designed to position the tip 14 a of thecannula 14 in the dermal layer in the injection position (FIG. 2).Although the epidermis and dermal layers of the skin S can have variablethicknesses, the cannula gap distance X is designed to result in the tip14 a being positioned in the dermis or at the lower portion of theepidermis in the injection position for the most common thicknesses ofthe epidermis and dermis of typical skin S. Accordingly, the combinationof the adapter 10 and the syringe 12 provide a relatively highlikelihood that the tip 14 a is positioned in the dermis or dermal layerand provides clinical benefit for the patient by applying the medicamentdirectly to the preferred layer of the skin S. Following injection, thesyringe 12 and adapter 10 are withdrawn away from the skin S, typicallyin an opposite direction from insertion and the syringe 12 and adapter10 are discarded.

Referring to FIGS. 1, 6, 7 and 8-12, in operation of the second andthird preferred embodiments of the adapter 10′, 10″, the injectionprocess is typically the same with the exception that the pre-filledsyringe 12 or pen injector 12″ without the cannula 14 is mounted to theproximal end portion 16 a′, 16 a″ of the body 16′, 16″ and the cannula14′, 14″ is fixed to the adapter 10′.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

1. An intradermal injection adapter having a cannula for making anintradermal injection, the adapter comprising: a body having alongitudinal axis; a central portion located distally relative to thebody along the longitudinal axis, the central portion having a cannulachannel therethrough extending generally parallel to the longitudinalaxis; a cannula within the cannula channel, the cannula having asharpened tip for injection into a patient and a sharpened oppositeproximal end for injection into a pen injector; and a distal protrusionhaving a first skin contacting surface extending generally parallel tothe longitudinal axis, the first skin contacting surface being spacedfrom the cannula such that a distal portion of the cannula extendsgenerally parallel to the first skin contacting surface.
 2. The adapterof claim 1 wherein the tip of the cannula is positioned approximatelythree to seven millimeters (3-7 mm) from a demarcation plane, the distalprotrusion and central portion being generally opaque proximallyrelative to the demarcation plane.
 3. The adapter of claim 1 wherein thecannula is fixed to the central portion.
 4. An intradermal injectionassembly for injecting a medicament into a dermal skin layer, theassembly comprising: a pen injector including a barrel and a plunger,the barrel having a generally cylindrical configuration and a hollowinternal cavity adapted to receive the medicament therein; and anadapter having a body, a central portion with a cannula channel fixedlyattached to a cannula, a distal protrusion with a distal nose, aproximal end portion and a longitudinal axis extending between theproximal end portion and the distal nose, the cannula having a sharpenedtip for injection into a patient and a sharpened opposite proximal endfor injection into the pen injector, the distal protrusion includes afirst skin contacting surface positioned generally parallel to thelongitudinal axis, a distal portion of the cannula spaced from the firstskin contacting surface at a cannula gap distance in the assembledconfiguration.
 5. The assembly of claim 4 wherein a tip of the cannulais located approximately one to six millimeters (1-6 mm) from the distalnose in the assembled configuration.
 6. The assembly of claim 4 whereinthe distal protrusion is generally transparent distally relative to ademarcation plane defined where the cannula crosses the cannula channeledge in the assembled configuration, the distal protrusion and centralportion of the adapter being generally opaque proximally relative to thedemarcation plane.
 7. The assembly of claim 4 wherein the distal nosecurves away from the longitudinal axis.
 8. A method of injecting amedicament into a dermal skin layer of a patient's skin utilizing anadapter and pen injector including a distal protrusion having arelatively transparent portion distally relative to a demarcation planedefined where a cannula crosses a cannula channel edge and a relativelyopaque portion proximally relative to the demarcation plane, a cannulafixedly attached to the adapter having a sharpened tip for injectioninto a patient and a sharpened opposite proximal end for injection intothe pen injector, and a first skin contacting surface positionedgenerally parallel to a distal portion of the cannula, a central portionand a longitudinal axis, the method comprising the steps of: a)attaching the adapter to the pen injector by piercing a closed distalend of the pen injector with the proximal end of the cannula; b) placingthe adapter proximate the patient's skin such that the longitudinal axisis generally parallel to the users skin; b) applying a force to the peninjector toward the skin and generally parallel to the skin to slide theadapter and pen injector along the patient's skin and insert the cannulainto the patient's skin; c) visually monitoring the insertion of thecannula into the patient's skin and the positioning of the patient'sskin relative to the first skin contacting surface through therelatively transparent portion of the distal protrusion; d) confirmingthat the cannula is at least partially positioned within the patient'sskin in an injection position; and e) injecting the medicament into thedermal skin layer.
 9. The method of injecting of claim 8 comprising thefurther steps of: withdrawing the adapter and pen injector away from thepatient's skin to remove the cannula from the patient's skin; and g)discarding the adapter and pen injector.